While making their press tour rounds, the cast of “Rampage” mentioned that they felt ridiculous acting against a green screen that would eventually become a giant albino gorilla. If that’s the case, it’s tough to fathom how they were able to spout out some truly insane dialogue. The urge to burst out with laughter must have been overwhelming.

However, as far as goofy popcorn action flicks go, “Rampage” is not terrible. There are actual attempts at character depth (failed ones, but they tried) and the CGI is fantastic. A handful of sequences are fairly intense and even a few that are actually ambitious for a movie based on an arcade game.

Like all of Dwayne Johnson’s movies, “Rampage” is markedly better than it should be due to his star power. Somehow, Johnson manages to make lemonade from lemons and he never seems bored with any of this material. He’s selling every moment like he’s shooting for an Academy Award nomination and that enthusiasm flies off the screen.

The story? Umm, here goes: an evil corporation’s failed science experiment blows up in orbit and a biological weapon falls to Earth that then turns three animals into huge mutated monsters and the only person that can stop them is primatologist Davis Okoye (Johnson). And yes, it is exactly as insane as you’re thinking it is.

In addition to having the coolest name ever, Davis Okoye does get some help from geneticist Dr. Kate Caldwell (Naomie Harris). She has some inside info on what’s turning Davis’ albino gorilla pal, George, into a three-story wrecking machine. Eventually, the two of them get wrapped up with government special agent Harvey Russell (Jeffrey Dean Morgan), a good ole boy with a six-shooter holstered on his hip.

And that’s it. Stuff explodes, buildings fall down and a giant wolf flies through the air. The sound level is cranked up so high that the only reason for it could be to audibly beat an audience into submission. The three animals do look fairly spectacular, particularly the gorilla, and they definitely do enough damage to live up to the movie’s title.

That’s about all the actors have with which to work. Naomie Harris has to say some really insane “science” stuff and she should be commended for keeping a straight face. The villains, played by Malin Akerman and Jake Lacy, are so horribly written that audiences may not despise them because they are evil. Instead, they may hate them because they are unbearably irritating.

Jeffrey Dean Morgan gets paid actual currency to do the same thing over and over. His devilish grin and country boy drawl is on full display and he’s even employing that off-kilter way of simply standing still. The crazy thing is that it’s enjoyable. Morgan’s wild card charisma seems to always work and if anything, he’s a world class curser.

“Rampage” could be the new poster child for how bizarre the MPAA ratings system is. This PG-13 movie is loaded with horrific, graphic violence, some of which was actually applauded during the screening. People are thrown about and swallowed whole by these giant beasts but thank goodness none of them said a few choice dirty words. The MPAA needs to think of the children here.

There’s really only one way to think of “Rampage:” another silly 107-minute exercise of watching Dwayne Johnson be Dwayne Johnson. He’s got loads of built-in appeal and some goodwill cache … but at some point, that’s going to run out and these movies simply must be better.